[gtk/modelbutton-focus] Adwaita: Give model buttons visible focus

[Matthias Clasen <matthiasc src gnome org>]

commit 7a06859f38484e2a1a6a9e8441ac9d876a8667f1
Author: Matthias Clasen <mclasen redhat com>
Date:   Fri Apr 19 21:33:17 2019 +0000

    Adwaita: Give model buttons visible focus
    
    Hard to use keynav, otherwise.  Also, hard
    to debug focus issues if you can't see where
    the focus is.

 gtk/theme/Adwaita/_common.scss | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index 2bb3f60447..7c71e3e1ac 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -16,6 +16,7 @@ $window_radius: $button_radius + 3;
   -gtk-secondary-caret-color: $selected_bg_color
 }
 
+modelbutton:focus(visible),
 button:focus(visible),
 checkbutton:focus(visible),
 radiobutton:focus(visible),